DAMPE detection of variable GeV gamma-ray emission from blazar CTA 102

      ATel #9901; Zun-Lei Xu (PMO), Micaela Caragiulo (Bari), Jin Chang (PMO), Kai-Kai Duan (PMO), Yi-Zhong Fan (PMO), Fabio Gargano (Bari), Shi-Jun Lei (PMO), Xiang Li (PMO), Yun-Feng Liang (PMO), M. Nicola Mazziotta (Bari), Zhao-Qiang Shen (PMO), Meng Su (HKU/PMO), Andrii Tykhonov (Geneva), Qiang Yuan (PMO), Stephan Zimmer (Geneva), on behalf of the DAMPE collaboration, and Bin Li (PMO) and Hai-Bin Zhao (PMO) on behalf of the CNEOST group. 

on 27 Dec 2016; 01:02 UT 

Credential Certification: Zun-Lei Xu (xuzl@pmo.ac.cn) Subjects: Gamma Ray, >GeV, AGN, Blazar, Quasar 

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     The DArk Matter Particle Explorer (DAMPE), has detected variable gamma-ray emission from a source positionally coincident with the flat spectrum radio quasar CTA 102 (also known as 4C +11.69) with redshift of z=1.037 (Schmidt 1965, ApJ, 141, 1295) and coordinates (J2000.0, from VLBI) of R.A.: 338.151704 deg, Dec.: 11.730807 deg (Johnston et al. 1995, AJ, 110, 880).  

     The DAMPE has recorded increased number of photons since November 23rd, 2016 UT, which is consistent with the optical and NIR brightenings of the source (for example ATel#9776, ATel#9801, ATel#9808, ATel#9821, ATel#9868). Our preliminary analysis shows a peak daily flux of ~(1.3+/-0.4) X 10^-6 photons cm^-2 s^-1 above 1 GeV, recorded on December 16th, 2016 UT. The daily light curve shows significant variabilities. The search for past data of DAMPE reveals relatively low state emission from April to June, 2016 when the source was within the field-of-view of the DAMPE. The highest energy of photons from the direction of CTA 102 ever detected by DAMPE is about 62 GeV. 

    This source was also detected by the 1-meter Chinese Near Earth Object Survey Telescope (CNEOST) of Purple Mountain Observatory. The magnitude is about 15.7 (sdss-r) at June 18.83, 2016 UT, which increased to 14.8 (sdss-r) at August 29.62, 2016 UT, 12.0 (sdss-i) at December 19.46, 2016 UT, and 12.1 (sdss-i) at December 22.48, 2016 UT. The CNEOST will keep on monitoring this source. 

     Enhanced activities of CTA 102 of this episode were also reported at the UV and X-ray bands by Swift (ATel#9841), the gamma-ray bands by AGILE (ATel#9743, ATel#9788, ATel#9840, ATel#9863) and Fermi-LAT (ATel#9869), and the radio bands (ATel#9884). 

     DAMPE is a space-borne calorimeter detector of high energy cosmic rays and gamma-rays. The detectable energy range is about 1 GeV to 10 TeV for gamma-rays. More information about DAMPE can be found at http://www.space.pmo.cas.cn/.  

  for more details : http://www.astronomerstelegram.org/